Explosively actuated device



Oct. 15, 1935, R. TEMPLE, JR

EXPLOSIVELY ACTUATED DEVICE 2 sheets-sheet 1 Filed-April 24, 1953 Oct. 15, 1935. R. TEMPLE, JR

EXPLOSIVELY CTUATED DEVICE Filed. April 24, '1955 2 Sheets-Sheet 2 INVENTOR ROBERT TEMPLE JR.

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ATTORNEY Patented Oct. l5, 1935 UNITED STATES PATENT oFFIcE ExrLosrvELr Ac'rUA'rEn DEVICE Robert Temple, Jr., Brooklyn, N. Y. Application April 24, 1933, serial No. 661,386

9 claims. (ci. 14o-14s) This invention relates to explosively actuated cutting devices and relates more particularly to an explosively operated device for cutting high amperage concentric cableswhile under a full load and without any appreciable arc and without danger to the operator.

Electric current is generally transmitted from the power house to the various divisions of the city or locality under high voltage and the volt- 10 age then stepped down in the divisional sub-station. The low voltage current is then transmitted to the individual users by means of a rubber insulated, lead covered, concentric cable. These cables frequently carry a current having four and five thousand amperes and when the rubber insulation becomes defective a short circuit occurs between the central portion of the cable and the lead covering, which latter is, of

course, grounded. When the'short circuit oc curs it is not expedient to open the entire circuit to replace the cable because large portions of the community would be without current. 'I-he cable must, accordinglybe cut as closely as possible to the short 'circuited portion. This is an exceedingly dangerous task and one slight error in the judgment 'of the operator will mean. instant and violent death. In the event that'the cablev is not promptly.'vv cut, however, there lsva' tremendous loss in cable lsince-the short circuit travels relatively rapidly in the directional the; power house and in the course of affew hours`f To this end the invention comprises an elongated structurehaving at one end thereof a semicirculartransverse recessin which the cable may be placed. A longitudinal slot provides a pas- 45 sageway in which the" knife travels. 'I he knife is mounted on a' piston which is actuated by explosive 'means employing a more or less conven tional blank cartridge. The relation between the cable supporting element, or recess, and the knife 50 is such that when the cartridge is fired the knife moves through the cable and moves completely past the cable supporting element. In other words, the longitudinal recess, in which the knife travels, extends beyond the cable supporting ele- 55 ment in order that the knife may move past the point where the cable is supported. In this fashion there can be no danger of the knife causing a short circuit after the cable has been cut. Also, there can be no return of the knife into the cable supporting element inasmuch as 5 the device is so, constructed that the explosive gases are retained intact in the explosion chamber after the explosion takes place and it is some minutes before these gases finally escape through the substantially air-tight spaces between the 10 piston and the cylinder or barrel which supports same. This retention of the gases, after the explosion takes place, likewise eliminates all re- Another object of the invention is to provide 15 a device of this kind wherein the knife, in its passage through the cable, will travel with tremendous speed due to the fact that the initial movement of the piston which carries the knife is retarded until the explosive gases have built 20 up their maximum pressure,v thereby securing the maximum efficiency from the relatively small charge of powder required to actuate the device.

The invention further contemplates the provision of a light'and compact cable cutting tool 25 which is mounted on a handle of suicient length that the device may be operated by inserting sanieinto a manhole wherein the cable is normally located andthe operator may actuate the device. from the street, thereby eliminating all 30 possible danger of operation.

Other objects and "advantages of the invention will be hereinafter specifically pointed out, or will become apparent,ias the specification proceeds.

With the above indicated objects in view, the invention resides in certain novel constructions and combinations and arrangements of parts, clearly described in the following specification and fully illustrated in the accompanying drawings, which latter show embodiments of the in# vention as at present preferred.

In the drawings:

Fig. 1 is a longitudinal, vertical section taken substantially through the center of the embodiment. c,

Fig. 2 is an elevation of the cutting end of the device. Y

Fig. 3 is a section taken on line 3-3 of Fig. 1.

Fig. 4 is a broken section taken on line 4 4 50 of Fig. 1. l

Fig. 5 is a perspective view of the knife or cutting member. k i v Fig. 6 is a broken perspective view of the knife in a slightly modified form.

' Fig. 7 is a longitudinal section taken through the center of the handle structure.

Fig. 8 is a perspective view of the piston.

Referring now to the drawings by reference numerals, the cable cutting embodiment, in its preferred form. includes an elongated barrel In which is constructed of hardened steel. The barrel is provided with a. longitudinal aperture II extending the full length thereof, said aperture having a reduced portion I2 adjacent to the cutting end of the device. Within this aperture a piston I3 is positioned and is adapted for longitudinal movement therein.

One end of the barrel is provided with an externally threaded portion I4, said threads being engaged by the internal threads I5 of a screw cap I6. The entire structure is supported, when in use, on a handle structure, described hereafter, the handle structure being screwed onto an externally threaded extension portion I1 of the cap I6. 'I'he cap is further provided with a longitudinal aperture I8 for a purpose hereinafter set forth. 'I'he aperture AII in the barrel is provided with an enlarged portion I9 at the outer end thereof to admit the iiange portion 20 of `a bushing 2| which functions as a buier for the piston after the longitudinal movement thereof is completed. The bushing has a central aperture 22, aligned with the aperture I8 in the cap, and is provided also with an externally threaded portion 23.

The piston I3 is provided with a threaded portion 25 at the end adjacent tothe cap I6, said threaded portion and the threaded portion 23 of the bushing 2| being engaged by opposite ends of a tension spring 26 which urges the piston in the direction of the cap. Adjacent to the threaded end portion 25 of the piston is a smooth portion 21 of the same diameter as the longitudinal aperture II in the barrel.

Immediately adjacent to the portion 21 is a reduced portion 28 of substantially the same length as the portion 21. Another and somewhat longer portion 29 is adjacent to the portion 28, said portion 29 closely tting the portion I2 of the longitudinal aperture II. adjoining portion 30 is of substantially half the diameter of the portion 29 and is provided with a threaded portion 3| at the end thereof.

The explosion chamber, which is designated as 33 prior to the detonation, is defined at one end thereof by the shoulder portion 34 on the piston. and at the other end thereof by the shoulder portion 35 which is formed by the reductiondn diameter of the aperture II, all as illustrated in Fig. 1. The piston moves rapidly toward the cap I6 and its movement is arrested when its end portion comes in contact with the bushing 2|. Inasmuch as there is no opportunity for the explosive gases to escape due to the precise iitting of the piston within the aperture, there is no recoil as a result of the explosion. It is appreciated, of course, that within a few minutes after the explosion the gases will have gradually escaped.

In Figs. 5 and 6 I have illustrated two forms of the knife, or cutting element, which is designated in Fig. 5 as 36. The knife includes a cylindrical'portion 31 at the lower end. said cylindrical portion having a longitudinal aperture 31' therethrough. The end portion 30 of the piston passes through this aperture and the knife is secured thereon by means of a cap nut 38. The cutting edge 38 is angular in shape and is provided with a bevel 40 on one-side only,

An immediately when it is actuated.

Ainto the recess 43 and the as illustrated in Fig. 5. In Fig. 6, however. the knife 36 is illustrated as having a straight cutting edge 39' and a double bevel 40.

The cable, which is designated as 42, is.` placed in a recess 43 in the cable supporting element 44. 'Ihe knife is adapted to pass through a longitudinal slot or recess 45 in the cable sup-, porting element, length so that when the knife has completed its stroke and is in'the position designated in broken lines at A in Fig. main in the recess 43. Each side of the recess 45 is provided with a removable liner 41 which is held in place by means of a screw 48 in order that-it may be removed if any wear occurs due to any slight arc which may take place.

said recess being of suiiicient 1, no portion thereof will reing and detonating the blank cartridge which is designated as 50. 'I'he barrel includes an upper fiat surface which is designated as 5I. A threaded aperture 52 passes from the upper surface of the barrel into the explosion chamber. Within this threaded aperture a cartridge supporting element or bushing 53 is positioned, said bushing having a longitudinal aperture 54 to receivethe cartridge. The bushing further includes an enlarged threaded portion 55, the lower end of which provides a shoulder 56 which engages a copper gasket 51 in order to seal the explosion chamber and prevent the outward passage of the gases. A breeching or firing pin supporting element 59 is screwed on yto the enlarged portion of the bushing. This breeching has a longitudinal aperture 66 therein in which a firing pin 6I passes. The firing pin is mounted at the lower end of the rod 62 having a handle 63 at the upper end thereof. The firing pin is urged downwards by means of a coil spring 64, said spring being supported at its upper end by means of a screw cap 65, said cap alsojserving to close the upper end of the aperture 60. I'he rod 62 which carries the firing pin is normally held in an upward position by means of a pin 61 having a ring 66 at one end thereof. Thus, when it is desired to fire the device a cord (not shown) which is attached to the ring 68, is pulled thereby allowing the firing pin to come in contact with the cartridge.

As heretofore stated, `it is desirable to mount the entire structure upon a handle in order that the operator need not be too close to the device The handle 10, which is illustrated in Fig. 7, is made from suitable insulating material and is provided witha longitudinal aperture 1I therethrough. .The handle is secured within a socket 12 which is mounted on the threaded portion I1 of the cap I6. Within the aperture 1I lof the handle, a rod 13 is mounted, said rod being secured at its outer end to a slidable handle structure 14 which is adapted for sliding movement on the handle 10. The handle structure 14 is urged to an outward position by means of a spring 15 which is mounted on the rod 13. The outward movement of the handle structure 14 is limited by stop meml bers 16.

The tension spring 26 normally holds the piston in engagement with the bushing 2 I, in which position the knife is located in the longitudinal recess 45 in the position shown in broken lines at A. When a cable is to bev cut, the handle structure 14 is moved forward, thereby causing the rod 13 to move the piston forward to the position wherein the knife will be located as shown in broken lines at B.; The cable is then inserted knife moves forward,

by virtue of the spring 26, to the position shown in full lines in Fig. 1, in whichposition it engages the cable. The pin 61 is then withdrawn thereby causing the firing pin to engage the cartridge. Thus, the kmfe moves swiftly through the cable and completely into the recess as shown at A.

It is important that the knife engage the cable, as shown, before the cartridge is fired, since the cable offers a resistance to the movement of the knife until the maximum pressure of the explosive gases has been built up in the explosion chamber, accordingly giving far greater momentum to the knife than would be the case if no resistance were afforded. In some instances where greater speed of the knife is required, a more positive resistance than is offered by the cable may be provided. This may be accomplished in the following manner. An aperture 18 is provided in the piston and another aperture I9 is provided in the barrel, the latter aperture being aligned with the former when the piston is in the starting position as shown in Fig. 1. A shear pin 80 of copper or other suitable metal is inserted with the aperture, as shown in Fig. 3, just prior to the firing. Thus, the movement of the piston is positively retarded, apart from the resistance afforded by the cable, until the explosive gases have been built up to their maximum pressure and when this is accomplished the pin 80 will be cut as well as the cable.

The hereinbefore described construction admits of considerable modication without departing from the invention; therefore, it is the wish not to be limited to the precise arrangements shown and described, which are as aforesaid, by way of illustration merely. In other words, the scope of protection contemplated is to be taken solely from the appended claims, interpreted as broadly as is consistent with the prior art.

What I claim is:

1. In a device of the class described, a cutting element, means for supporting the cutting element, explosive means for actuating the cutting element, and means for confining the explosive gases for preventing recoil of the supporting means.

2. In a device of the class described, an apertured barrel member having a transverse recess at one end thereof and a longitudinal recess adjacent to the transverse recess, a piston carried within the aperture of the barrel, a knife mounted on said piston and adapted for movement in the longitudinal recess, explosive means for actuating the piston and means for confining the explosive gases after the charge is set olf.

3. In an explosively actuated cable cutting tool, an elongated barrel having a longitudinal aperture extending therethrough, a portion of the aperture adjacent to the cutting end of the tool being smaller than the aperture at the opposite end thereof, a bushing positioned within said opposite end and a screw cap to secure said bushing in place, a piston positioned within said aperture, said piston having a reduced portion to provide a shoulder to receive the impact from the explosive gases, said barrel having at the cutting end thereof, a cable supporting portion having a semi-circular recess to support the cable. said latter portion also having a longitudinal recess, a knife carried on said piston and adapted to move within said recess, said recess being of sufficient length to allow the knife-to pass completely past the cable supporting recess after the cable has been cut, a cartridge supporting bushing mounted on said barrel, a cartridge supported 5 within said bushing and means for firing the cartridge.

4. In a device of the class described, a cutting element, means for supporting said cutting element, means for actuating said cutting element, said latter means comprising a confined explosive charge, and means for retarding the initial movement of the cutting element until a substantially maximum pressure of the explosive gases has been built up, and means for moving the cutting element beyond the member to be cut after same has been severed.

5. In an explosively actuated cable cutting tool, an elongated barrel having a longitudinal aperture therein, a longitudinally movable element 20 positioned within said barrel, a cutting member carried at one end of said element and explosively actuated means positioned at the opposite end thereof, and a bifurcated cable supporting element through and beyond which the cutting member may pass after the cable has been severed.

6. In an explosively actuated tool for cutting live cable, an elongated barrel having a longitudinal aperture therein, a longitudinally movable elongated element positioned within said barrel, a cutting member carried at one end thereof, and a piston member carried at its opposite end, explosively actuated means positioned between said piston and said cutting element, and a cable a5 supporting element beyond which the cutting member may pass after the cable has been severed.

7. In an explosively actuated device for cutting live cable, an elongated barrel having a longitua) dinal aperture therein, a longitudinally movable elongated piston positioned within said barrel, a cutting element carried at one end thereof, a shouldered portion at the opposite end thereof to form a piston portion against which theA ex- 5 plosive gases may act, and a slotted cable supporting element through and beyond which the I cutting element may pass after the cable has been severed.v Y

8. In a cable ,cutting device of the class de- 50 scribed, the combination of an apertured barrel member, having a longitudinal recess at-one end thereof, and a cable supporting element adjacent to said recess, a longitudinally movable element positioned within said barrel, a cutting device carried at the rear end of said element and adapted to move within said recess and pass beyond said cable supporting element after the cable has been severed, a shouldered portion at the front end of said longitudinally movable element which forms' a piston, and explosively actuated means adiacent to said piston for actuating same.

9. In a device of the class described, the combination of an explosively actuated cutting elel ment and a support for the article to be lcut, said 65. support having a slot through which the cutting element may pass after the article has been severed, the slot being of sufficient length to permit 

